Every time I saw this happen in the 90s the result was the same: Small team shows up in big company after big $$, gets frustrated with big company BS, doesn't really care and runs down the game clock until vesting is nearly complete, leaves without fanfare.
I'm sure there must be counter examples, please let me know some if you have them.
I wonder if the reason alot of acquired entrepreneurs leave is that they are used to having so much authority and latitude that getting a middle manager role at google just feels like wearing a straight jacket.
Google had Foursquare in house (called Dodgeball) but couldn't execute.
Android is the best counter-example I can think of.
Measure Map was a small team acquired by google that made a pretty analytics app for blogs and they went on to overhaul Google Analytics, which at the time still look pretty rough because it was an acquired app (Urchin) that was made for power users.
That team worked pretty well. After everyone vested, Jeff Veen put the band back together and they started cranking out other apps, first WikiRank and then Typekit, which was just bought by Adobe.
I can see the parallels with Milk: 1) a small interdisciplinary team that works well together and with a kickass designer (Daniel Burka) that has a knack for making the complex look simple, and 2) an app like Google+ that's just as important to their new core mission as Analytics was to their old one and also has similar room for improvement.
Do remember when the bubble collapses, you will be hurt far more than the players who already made their millions and can weather the collapse.